Microsoft will make Windows Defender Beta 2 available for Windows 2000, XP, 2003, R2, Vista and LH server. Beta 2 will be released in February / March. 64 bit versions will be included in Vista / LH Server x64 editions and for XP and 2003 x64 editions.Windows Defender will be configurable via Group Policies, and defender updates will appear on WSUS. Defender updates will be released as needed, from few times a day to minimum once a week through (automatic) Windows Update infrastructure.Beta 2 will have significant changes according to the chat transcript held by the Windows Defender team. Full Chat At Source